Depending on the context (resume, case study, about page, Linkedin profile, etc.) and variety of types, I would stick to 5-10 items. I would look at the toolkit that the company uses and is looking for in that job, and prioritize those in your application.

If you don’t have a specific list to target, I would suggest researching similar jobs/companies to see what kind of tools are mentioned the most and prioritize the ones that are the most important to the kind of role you are aiming for. For example, Adobe Illustrator is rarely an important tool for a UX designer, and so on. An additional parameter I would take into account is how often I use the selected tools. If I used something twice a year, I might deprioritize it to free up space for more used tools. Also, I would consider the trends and the more future-proof tools that will likely to stay or has more potential to stick around. Also, I would consider if there may be a (relevant) tool that you are the best in the world.

Indirectly, your ability to choose only a limited subset of options from a bigger set might signal to the reader that you are familiar with the concept of prioritization, which is important for a UX role.

That being said, I would not be too focused on the tools. If you have learned somewhat relevant tools, chances are you can also quickly learn a similar tool that a particular company uses. Learning new tools is the least of the worries of a potential (smart) hiring manager. The ability to learn quickly, knowing the design process, evidence that you can deliver results and produce high-quality work working on a team are more important elements than knowing particular tools. I heard this from many hiring managers - specific tools are not as important, tools are the easiest to learn.